The present invention relates to a resin impregnation and molding technology for porous material of interposing a porous material, which is mica or a glass fiber, between a solid member and another member. In particular, the present invention is concerned with a method for analyzing growth of void of resin in porous material suitable for a three-dimensional fluid analysis technique and capable of comprehensively estimating production, growth, fluid behavior, and distribution of voids in a resin in a porous material in the course of impregnating and molding the porous material.
As related arts concerning a resin fluidity analysis modeling method for porous material employed in impregnating and molding a porous material, there are related arts described in Japanese Patent Application Laid-Open Publication Nos. 2008-230089 and 2006-168300. As a void-production estimation method for a resin-molded product, there is a method described in Japanese Patent Application Laid-Open Publication No. 2009-233882.
Japanese Patent Application Laid-Open Publication No. 2008-230089 has disclosed, in relation to a resin flow in a porous material, a technology for a calculation method of inputting a three-dimensional pressure loss as a product of a cross-sectional specific resistance representing a flow resistance, a viscosity, a velocity, and a flow distance.
Japanese Patent Application Laid-Open Publication No. 2006-168300 has disclosed, in relation to a resin flow in a porous material, a technology of modeling and calculating an impregnated state of a substrate on the basis of the Darcy formula.
Japanese Patent Application Laid-Open Publication No. 2009-233882 has disclosed, in relation to production of voids in a resin-molded product, a technology of obtaining an elasticity of a resin and a contractile force thereof from the resin temperature in a microscopic element, and estimating voids through structural analysis.
A method of impregnating a porous material with a resin and molding the resultant medium is adopted for a stator coil insulation layer of a power generator or a motor, or blades of a wind generator. The impregnated molded product is characteristic of being lightweight and highly strong, and the application range thereof is expanded even to an airplane chassis.
When voids are generated in a resin to be made into an insulation layer, if a high pressure is applied, discharge occurs through the voids. This leads to dielectric breakdown. If voids are generated in a resin in a fiber-reinforced plastic (FRP) product that is a lightweight and highly strong impregnated molded product, such as, blades of a wind generator, the voids originate breakdown. This poses a problem in that the strength of the FRP product is markedly degraded. Production and growth of voids are attributable to gas generated at the time of heating a porous material in which an organic solvent remains, a solid member that contains an organic substance and adjoins the porous material and a resin, and a resin material. In order to minimize generation of voids due to the gas generated from the porous material or solid member, it is necessary to review modification of a drying process preceding resin impregnation, modification of conditions for a resin heating and curing process, changing of the materials of the porous material and solid member respectively. However, it costs high to experimentally review the above contents, and prolongs a development period. Therefore, development of an analysis technology capable of comprehensively estimating production, growth, fluid behavior, and distribution of voids in a resin is needed. Using the analysis technology, conditions under which production of voids is minimized have to be determined.
As for the related arts, Japanese Patent Application Laid-Open Publication Nos. 2008-230089 and 2006-168300 describe fluidity analysis of a resin in a porous material, but do not mention an analysis method for analyzing generation, growth, fluid behavior, and distribution of voids occurring in the course of heating and curing of the resin. In addition, the patent document 3 describes analysis of production of voids due to contraction of a resin, but does not mention an analysis method for analyzing production of voids due to generation of gas from the porous material, a solid member, and the resin.